Mounting for compound telescope having parallel optical axes



March l, 1966 M. KRAJowsKY E'rAL 3,237,518

MOUNTING FOR COMPOUND TELESCOPE HAVING PARALLEL OPTICAL AXES o Y v T l/l 1.,v n 3. mm. Q. m. n .mwwpu m rom. @9 MMT ....02 f 59 mKL. p mm. a! 3LE 5. EN m ..1x-. nm. ME f il? 2. v M... D! Q! NNN: am. m0. mm1 um. vm.n!

ATTORNEY March l, 1966 M. KRAJowsKY ETAL 3,237,518

MOUNTING FOR COMPOUND TELESCOPE HAVING PARALLEL OPTICAL AXES OriginalFiled Feb. '7, 1962 3 Sheets-Sheet 2 INVENTORS KRAJOWSKY L. TU R N E RATTORNEY March 1, 1966 M. KRAJowsKY ETAL 3,237,518

MOUNTING FOR COMPOUND TELESCOPE HAVING PARALLEL OPTICAL AXES 5Sheets-Sheet 5 Original Filed Feb. 7, 1962 INVENTORS MICHAEL KRAJOWSKYEUGENE L. TUR BY 73 NER MG@ AT TO RNEY United States Patent O 4 Claims.(Cl. ss-sz) This application is a division of our copending applica-vtion Ser. No. 171,680, filed Feb. 7, 1962, now abandoned.

The present invention relates to a compound telescope and moreparticularly it relates to the mounting mechanism for the optical partsthereof.

Although astronomical and other compound telescopes have been made formany years in a great numlber of forms for portable use, the need for aninstrument which could be used to continuously vary or zoom themagnication of the image during observation has not been met. It isoften desirable when conducting a search for comets or when searchingfor other celestial bodies to be able to change the size of the field ofview and/or the size of the observed Aobject quickly and smoothly. Thisaction is particularly useful when the object under o servation istransitional in character or rapidly moving. The same desirable featuresare useful also in corresponding terrestrial observations.

In view of the desirability of the aforementioned features, it is anobject of this invention to provide a novel compound telescope, such asfor instance an astronomical telescope, having means by which themagnification of the observed image may be quickly and continuouslyVaried.

It is a further object to provide such a telescope which iscomparatively light and portable, compact and of good appearance.

It is another object to provide such a device wherein the optical partsare reliably and strongly mounted and held in precise alignment witheach other during all operating posit-ions of the moving parts thereo-ffor improving the optical performance.

A further object is to provide a compound telescope at least costconsidering its hi-gh standard of performance and other advantageousfeatures embodied therein, said telescope being adaptable by reason ofits peculiar construction to a considerable number of diverse seeingtasks.

Another object is to provide such a device which is easy to operateeither manually or by power, and by reason of its eyepiece designaffords comfortable seeing postures for the observer, all of the workingparts thereof being compactly arranged and well enclosed and protectedagainst the deleterious effects of foreign matter and moisture.

These and other objects and advantages are to be found in the detailedform and arrangement of the component parts of this invention and in thecombinations thereof as found in the specification herebelow, taken inconnection with the accompanying drawings, wherein:

FIG. 1 is a side elevation of the front portion of a telescope embodyingthe present invention, parts thereof being shown in section and partlybroken away;

FIG. 2 is a partial side elevation of the rear portion of saidtelescope, parts thereof be-in-g broken away and shown in section;

FIG. 3 is a sectional view taken on the line 3-3 of FIG. 1;

FIG. 4 is a partial sectional View taken on the line 4-4 of FIG. 1 of anoperating mechanism comprised in the telescope;

FIG. 5 is a partial sectional view taken on the line 5-5 of FIG. 2;

3,237,518 Patented Mar. 1, 1966 lCC FIG. 6 is a perespective view of anoperating subassembly comprised in said telescope, parts thereof beingshown fragmentarily and in section;

FIG. 7- is a plan view `of an operating mechanism for a part of thetelescope;

FIG. 8 is a sectional view taken on the line 8-8 of FIG. 1; and Y lFIG.9 is a side view of certain operating structures lshown partly insection taken on the line 9--9 of FIG. 4.

A preferred form of thisvinvention is shown partly in FIG. 1 of thedrawing where the numeral 10` designates the telescope generally. Fors'turdiness and rigidity, au elongated casing 11 is provided having awide zone 12 and a narrow zone 13 which are integrally formed with eachother for the purpose of housing the mounting mechanism for the opticalparts.

The telescope 10 comprises two groups of optical parts,-

one group called the catadioptric or teleobjective group being alignedalong a first optical axis 1-4 in zone 12 of the casing and shownjointly in FIGS. 1 and 2, and the second group called the nder telescopebeing aligned in the narrow zo-ney 13 o-f the casing along a second axis15 which is parallel to axis 14, said nder telescope also having theauxiliary scanning function as found in large telescopes. It-will beseen that about half of the mechanism of the teleob-jective group andhalf of the mechanism of the finder telescope group is shown in anysingle drawing.

Referring first to the catadioptric group, the light rays enter thetelescope 10 through a corrector lens 16 having a rear surface 17. Saidlens 16 is held on a lens seat 18 formed in the wide zone 12 of thecasing 11, said seat terminating rearwardly in an annular shoulder 19against which the lens surface 17 is held. For urging the lens 16against shoulder 19, a ring nut 20 which is threaded on the innersurface of said casing isiutilized and a suitable sealing ring 21 isheld under pressure between the nut and the lens.

Coaxially with the rcorrector lens 16 and rearwardly thereof is mounteda spherical mirror 22, the reflective surface 23 thereof being held forgood optical alignment against a partial annular shoulder 24 formedwithin the wide zone 12 of the casing 11. Contiguous to said shoulder 24is formed a cylindrical seat 25 which is radially spaced from theperiphery of thev mirror as shown in FIG. 2.

For the purpose of locking the mirror 22 permanently on its seat 25subsequent to being seated against the shoulder 24, a suitablethermoplastic resinous cement 26 is forced through a plurality of radialfeed holes 27 which are formedl in the casing 12 as shown in FIG. 5 soas to provide a plurality of pads on which the mirror is solely held,both radially and axially.

Image rays reected by the mirror 22 are directed onto a flat mirror 28which is obliquely held so as to deflect said rays laterally of axis 14toward the axis 15. Said flat mirror 28 is preferably rst adhesivelysecured by a suitable cement onto an inclined face 29 of a hollow centerpost or stand 30 on which a shouldered pilot 31 is formed. Lens 16 isbored at the center to receive said pilot 31 and the mirror and standare assembled therein. Said mirror 28 is rst assembled on post 30, whichis then assembled on lens 16 and is cemented therein after the mirror 28has been properly aligned With the iinder axis 15. This operation iseffected by means of inserting a tool in a slot 32 and rotating themirror stand 30 until optical alignment is established.

In the narrow zone 13 of casing 11 is mounted the second optical groupwhich receives the image rays from the catadioptric optical system ontoan adjustable and movable inclined mirror 33 as described hereinafter.

f In the preferred form as shown jointly by FIGS. lj 2 and 6, the findertelescope includes in progressive order and in mutual optical alignmenton the A'axis 15 an objective lens member 34, a focusing' lens member35, a field lens 36, a zoom lens system 37 consisting of a front zoomlens 38 and a rear lens 39. Aligned rearwardly thereof in the findergroup is an erector lens member 40 and 'a subsequent eyepiece 41. Y, Y

Advantageously for optical alignment and rigidity purposes, all of theabove-recited optical components except the eyepiece 41 in the finderoptical' group are held in a stationary mounting tube 42 which isclosely fitted at its forward end in a bearing 43. 'Said bearing isformed in a front wall 44 which is preferably constructed integrallywith said casing 11. The rear support for the mounting tube is describedhereinafter in connection with the eye piece mounting.

In the front end of the stationary mounting tube 42 a first lens cell45, wherein the objective lens 34 is secured by any suitable means suchas cementing, is preferably threaded for axial and suitable lateraladjustments there- Rearwardly of lens cell 45,y a second lens cell 46 isprovided wherein the focusing lens 35 is suitably fixed as, bycementing, said cell having a rearwardly extending tube 42 is astationary lug 51 wherein a pivot pin 52 is suitably fixed on which saidoperating lever 50 swings. At the point of engagement of the actuatingpin 48, a free-fitting elongated slot 53 is formed in one end` of theoperating lever 50 to provide therewith a relative sliding connection.50 similar pin and slot connection generally indicated by numeral 54 isprovided, the pin thereof being fixed in a nut 55 which is threaded on acontrol shaft 56. The shaft 56 is suitably journaled in a bearing 57mounted in said casing 11 and projects outwardly therefrom so that anexterior control knob 58 may be fixed thereon. For preventing backlashin the above-described operating mechanism, a suitable tension spring 59is anchored at one end to a stationary peg 60 and at its other end isattached to the actuating pin 48.

Rearwardly of the focusing lens 35, the field lens 36 is fixed in anelongated lens cell 62 byy any suitable means su-ch as cementing. Saidlens cell 62 is fastenedy in a fixed position in the mounting tube 42 bytwo screws 63 which are 90 apart and which are held in fitted openingsin said tube and are threaded into tapped holes in the lens cell `62.

Spaced still further rearwardly in the stationary mounting tube 42 isthe aforesaid zoom lens system 37 comprising front zoom lens 38 which isadjustablyfheld in a movable zoom lens cell 64. Preferably the lens 38is cemented directly in a lens holding ring 65 which is threaded forlongitudinal adjustment within the cell 64. For effecting zooming motionof the zoom lens 38, a zoom actuating pin 66 is suitably anchored in thelens cell 64 so as to project radially through a slidably fittedstraight slot 67 formed longitudinally in the mounting tube 42 andengage slidably within a curved slot 68 formed in an operating sleeve69, as shown in FIGS. 1 and 6.

For mounting the aforesaid rear zoom lens 39, a second movable zoom lenscell `70 is provided` wherein the lens is suitably fixed as bycementing, said cell being slidably fitted within the mounting tube 42.Zooming motion is communicated to the lens cell 70 by a pin 71 which issecured in said cell radially by thread means On the other branch of thebell crank lever 4 7,2 sothat said pin extends through an axiallydisposed slidably fitted straight slot 73 formed in the mounting tube42. Said pin '71 extends outwardly therebeyond through a slidably fittedhelical slot 74' formed in the operating sleeve 69 and is engagedtightly at its outer end igithii: a closely fitted bore 75 formed in anoperating The means for actuating the zoom optical system 37 embodies anovel and advantageous combination or mechanism which is shown generallyin FIG. 6 and in 'a lesser degree in FIG. l. As best shown in FIG. 6,the zoom actuating force is a longitudinal force applied solely by theoperating bar 76 through the Zoom actuating pin 71 in the firstinstance, directly to the zoom lens cell 70 and in the second instance,a rotary force is transmitted therefrom to the second zoom lens cell 64indirectly through the operating sleeve 69.

With regard to the operation of the lens cell 70, the operating sleeve69 is rotatably mounted on the outer diameter of the stationary tube 42and is restrained from relative longitudinal motion thereon by a pin 77FIG. 2 which is fixed in any preferred manner such as the thread 78 inthe,` wall of the stationary mounting tube 42. Said pin 77' cooperateswith a transverse circumferential slot 79 of required angular extentwhich is formed in the operating sleeve 69 in suchv a manner as tofulfill its stated purpose.

By the above-described mechanism, the zoom actuating pin 71 in itslongitudinal travel causes the operating sleeve 69 to rotate through theaction of the helical slot 74 so that the irregularly curved slot 68consequently rotates and moves the zoom lens cell 64 axially. Thisarrangement and construction of the zoom actuating mechanism has, amongother features, the distinct advantage that it is reversible and easilyoperated with substantially equal operating force in either directionwhile at the same time the configuration of the slots 68 and 74 is sochosen as to cause properly related motions of the zoon lens cells 64and 70.

The aforesaid operating bar 76 is mounted slidably for longitudinalmotion in an elongated slot 80 formed in the underside of an elongatedhousing 81 in such a spaced relation to the outer diameter of theoperating sleeve 69 that together these parts form a four-sided channelwherein the bar travels. In order to hold the housingl 81 in such aposition, laterally protruding feet 82 and 83 are formed on the oppositeends thereof in spaced relation to the ends of the Operating sleeve 69and are secured by suitable means such as screws 84 and 85 which projectthrough openings in said feet and are threaded into tapped holes in thestationary tube 42.

Manual and/ or power means are provided to move the i operating bar 76comprising a rack 86 formed along one edge of said bar as shown in FIG.6. In meshing engagement with the rack 86, is provided a primary drivegear 87, said gear and a secondary drive gear 88 being rotatably mountedtogether on a shaft 89. A suitable friction 'drive Iclutch 90 is locatedbetween the gears 87 and 88 and the effective pressure of tlhe clutch isprovided by a suitably arranged disk spring 90 seated beneath a nut 89which is threaded onto shaft 89.

The primary drive gear 87 is fixed in any preferred manner, such as thedrive pin 87', to said shaft -89 and on the other end thereof a knob 91is secured for manual operation thereof. In mesh with the secondarydrive gear 88 is a drive pinion 92 which is drivingly connected by asuitable connecting device such as a set screw 93 to a power shaft 94and to a gear box 95 which is part of a motor 96 whereby gear 88 isrotated. By this mechanism the rack `86 may be moved manually `t-o zoomthe lens system when the motor 96 is idle. For energizing the motor 96an operative electrical circuit including the conductors 97 and 98 and areversing switch 99 is provided in connection with a source ofelectrical power, as indicated in FIG. 6.

The rear end of the casting 11 is closed by a closure plate or cover 100which is secured demountably around its periphery to said casing by capscrews 101 which extend through screw holes in the cover and arethreaded into corresponding tapped holes in said casing, Closure plate100 is not only used as a cover to exclude foreign matter and moisturebut it also effectively serves as a support for the rear end of thestationary mounting tube 42. For this purpose, a bore 102 is formed inthe cover 100 and into said bore is fitted a tubular coupling orretainer member 103 which is threaded at 104 into a mating thread formedon the inside surface of said tube 42. In its midsection, a radialshoulder 105 is formed on coupling member 103, said shoulder being drawninto abutting position against the cover plate 100 by the threads 104 toclamp the rear end of the tube 42 against said plate. A lock screw 106threaded into the wall of the coupling or retainer member 103 serves toprevent various stresses and vibration from releasing or loosening theclamping action. Forwardly of the shoulder 105 on the coupling member isformed a cylindrical bearing surface 107 which is closely fitted to theaforesaid bore 102, said surface being extended forwardly of said boreso as to slidably fit within a corresponding counterbore 108 formed inthe rear end of mounting tube 42 whereby the tube is accuratelycentralized with the coupling member and a strong support therefor isassured. To prevent the stationary mounting tube 42 from rotating, andautomatically providing alignment between internal and externalcomponents, a parallel-side notch 109 is formed in the rear end thereofand an axially projecting element such as a pin 110 is secured in theclosure plate 100 and fitted between the sides of the notch.

In the rear end of the mounting tube 42, an abutment shoulder 111 and acontiguous lens seating surface 112 are formed whereon the erector lens40 is held, said lens being clamped against the shoulder 111 by aclamping ring 114 threaded into a thread formed on the interior of tube42.

In this respect, it is important to note that the coupling or retainermember 103 is so constructed as to serve a plurality of functions whichare: (1) To clamp the mounting tube 42 against4 the plate 100; (2) tolaterally locate the tube 42 with regard to the plate 100 to providereliable optical alignment of the lens system; (3) to serve as a supportmember for carrying the eyepiece housing of the instrument as describedhereinafter.

On the rear end of the coupling member 103 an eyepiece housing which isgenerally designated by the numeral 115 is carried. For locating thehousing 115 laterally and longitudinally with reference to said couplingmember, an annular surface 116 and a contiguous abutment shoulder -117are formed on the rear end of the coupling member whereon an annularextension 118 of housing 115 is fitted. Forwardly spaced from theshoulder 117, a radial clamping surface 119 is formed on the couplingmember 103 against which a clamping ring 120 is adapted to be clamped toprovide a swivel connection between the member and the housing. To thisend, a threaded connection 121 cooperatively formed on the adjacentparts of the clamping ring 120 and the eyepiece housing 115 is providedto secure the two members together in any desired relative angularorientation.

In the body of the housing 115 is provided a movable fiat mirror 122which is inclined in one operative position at 45 to the optical axis 15so as to deflect image rays laterally along an optical exis 123 which isa property of the eyepiece lens 41. The lens system 41 is mounted in alens cell 125 which is slidably fitted within a counterbore 126 formedin an eyepiece mounting tube 127 which is secured by the threadedconnection 128 into a lateral opening 129 in the eyepiece housing 115. Aset screw 130 is threaded into a tapped hole in tube 127 to lock thecell 125 in the counterbore 126.

When the mirror 122 is positioned to serve a laterally positioned lenssystem 41, the reflective surface thereof is coincident with the pointof intersection of the axes 15 and 123. A second opening 131 which iscoaxial with axis 15 is formed in the end wall of the housing 115 andthis opening is threaded exactly like the opening 129 so that theeyepiece tube 127 may be used in axial position if desired. Tofacilitate such a use, the mirror 122 may be swung about the axle 132 ofits mounting mechanism to the dotted line position 122', FIG. 2, so thatthe image rays pass directly through the opening 131. Suitable detentmechanism 133 of any preferred design such as shown in FIG. 2 isprovided in operative connection to the mirror mounting mechanism toreliably retain the mirror 122 in either of two operative positions. Aremovable closure cap 134 is provided for the opening 131. Mirror 122 ismounted by suitable 4tip and tilt adjusting mechanism, constructed onits support 12251, so that optical alignment of the optical system maybe accomplished in much the same manner as that described hereafter inconnection with the mirror 33.

As aforesaid, the plane mirror 33 is movably mounted to swing about theaxis of a mounting shaft 135 as best shown in FIG. 4 so that the mirrorhas an operative position extending at 45 degrees inclination to theaxis 15 as indicated in full lines or it may be moved to the inoperativeposition indicated by dotted lines 3 3V in FIG. 1 when it is desired touse only the finder telescope. On shaft 135 is held a mirror frame 136by means of a mounting stud 137 which is threaded at one end into ananchor block 138, said block being fixed by the crosspin 139 to shaft135 so that mirror 33 is held in alignment with a pair of oppositelyformed openings 140 and 141 in the mounting tube 42.

Axial positioning of the mirror 33 is secured by threading the frame 136onto the other end of the stud 137, the threaded connection actuallybeing formed in a nut 142 which is rotatably held in said frame.

Adjustments for tip and tilt of the mirror 33 are provided by afiixing amirror block 143 adhesively to the mirror and interposing a singlebearing ball 114 between the mirror block 143 and mirror frame 136.Three adjusting and holding screws 145 which are angularly and radiallyspaced about the ball 144 are passed through loose holes in the frame136 and are threaded into the mirror block 143 so that by selectiverelative adjustments of the three screws, an infinite variety ofadjustments for tip and tilt of the mirror are effected.

In the casing 11 is formed an opening wherein a suitable sleeve bearingmember 146 is suitably secured. Through the center of said bearingmember, a bore 147 is provided in which a shaft extension 148 of shaft135 is journaled. Shaft extension 148 projects outwardly of the casing11 and on the outer end thereof a manually operated knob 149 is fixed bywhich the aforesaid swinging motion of mirror 33 is effected.

As best shown in FIG. 4, the shaft 135 is supported near its inboard endin a curved mounting plate 150 having a bearing portion 151 formedthereon which is bored to fit and rotatably hold the operating shaft 135therein in good alignment with the sleeve 146. For aixing the curvedplate 150 to the mounting tube 42, suitable screws 152 extend throughfitted holes in said plate and are threaded into tapped holes in saidmounting tube.

For the purpose of holding the mirror 33 in either operative orinoperative position, detent means are provided as shown in FIG. 9 ofthe drawings. Said means comprise a fan shaped plate 153 having a hub154 which is secured to the shaft 135 by a cross pin 155. The plate 153is provided with a working surface along its edge in which two angularlyspaced notches 156 and 157 are formed in operative and inoperativepositions respectively. Cooperating with the notches 156 and 157 is aspring detent of any desired form such as the ball 158 which is retainedin a bore formed in a boss 159. Said boss is preferably made integralwith the curved plate 150 and in said bore is retained a detent spring160 seated against a threaded plug 161, said spring being seated at itsupper end against said ball 158 to apply pressure thereto.

A study of the foregoing description discloses many advantageous usefulfeatures which include a rigid selfcontained and sturdy housing and arelatively simple, rel-iable and precise means of mounting the componentoptical parts of the telescope particularly the zoom optical system,said parts being rela-tively adjustably fixed therein and being wellenclosed to protect said parts from damage of foreign material,mechanical damage or moisture.

Although only a preferred form of this invention has been shown anddescribed in detail, other forms, modifications and arrangements may bemade within the spirit of this invention as defined in the claimsappended hereto.

We claim:

1. A catadioptric astronomical telescope having a zoom type of opticalsystem and a catadioptric optical system cooperatively 4associated andaligned on two parallel optical axes,

a tubular casing wherein said Zoom system and said ca-tadioptric systemare mounted and housed,

an end wall formed in the front end of said casing and a circularbearing surface defining an opening formed therein,

a rear closure wall demountably secured to the rear end of said casing,a stationary mounting tube wherein said zoom system S held,

means operatively formed on the forward end of said stationary tube andfitting said circular bearing surface for supporting said tube,

inter-fitting means cooperatively formed in said closure wall and on therear end of said stationary mountingl tube for supporting the rear endof said tube in said closure wall,

means for securing said catadioptric optical system in operativeposition on one of said axes in said casing, and

mirror means operatively arranged between said zoom system andcata-dioptric system for relaying image rays from one system to theother.

2. A compound telescope having in combination a zoom type of opticalsystem and a catadioptric optical system cooperatively associated andaligned on two parallel optical axes,

a tubular casing,

a corrector lens and a spherical mirror comprised in said catadioptricsystem,

means for holding said lens and mirror in optical alignment with eachother and with said zoom system in the front and rear parts respectivelyof said casing,

a stationary tube wherein said zoom system is mounted,

means in the front end of said casing for demountably holding the frontend of said tube in laterally spaced relation to said catadioptricsystem,

a closure plate for the rear end of said casing,

means longitudinally aligned with the means for holding the front ofsaid tube for securing the rear end of said tube to said plate so thatsaid tube and plate form a sub-assembly, and means for demountablyattaching said closure plate to the casing whereby the zoom opticalsystem may seperately be assembled on land disassembled from the casingwithout disturbing said catadioptric system.

3. A ltelescope as set forth in claim 2 wherein the means for securingthe rear end of said stationary tube is characterized by a circularseating surface which defines a bore in said plate and is furthercharacterized by a coupling member having an annular surface which isfitted within said circular seating surface and having an abutmentshoulder formed thereon at the rear terminal portion of said bearingsurface for abutment against the outer surface of said closure plate,said coupling member having a cylindrical extension which is fitted toand carries the rear end of said tube,

an eyepiece housing, and

means cooperatively formed on said coupling member and housing forsupporting the housing on the member. p

4. Mechanical mounting mechanism for compound astronomical telescopehaving a zoom optical system and a catadioptric system which arecooperatively aligned on parallel axes,

a casing in which the zoom system and catadiotric system are held,

a stationary tube in which said Zoom system is mounted,

a closure plate demountably secured to lthe rear end of said casing andhaving formed therein a circular seating surface which defines anopening through the plate,

a coupling member whereon a cylindrical surface is formed so as toclosely t said seating surface,

an abutment shoulder formed on the coupling member adjacent to the rearof said cylindrical surface for contact with said plate, saidcylindrical surface having a connecting portion formed thereon andprojecting Within said stationary tube,

a threaded connection cooperatively formed on said connecting portion.and tube so as to clamp the plate between the end of said tube and saidshoulder,

an eyepiece housing wherein a laterally directed eyepiece is held, and

a swivel connection including a pair of circular intertted bearingsurfaces which are formed on the housing and coupling memberrespectively substantially concentric with the optical axis of said zoomoptical system, the connection being operatively constructed so that thehousing may be clamped to the member in any angular position andmaintain the optical alignment with both of the aforesaid opticalsystems.

References Cited by the Examiner UNITED STATES PATENTS 2,409,186 10/1946Bouwers 88-32 2,988,955 6/1961 Goto et al 88-57 FOREIGN PATENTS 603,5696/ 1948 Great Britain..

IEWELL H. PEDERSEN, Primary Examiner.

1. A CATADIOPTRIC ASTRONOMICAL TELESCOPE HAVING A ZOOM TYPE OF OPTICALSYSTEM AND A CATADIOPTRIC OPTICAL SYSTEM COOPERATIVELY ASSOCIATED ANDALIGNED ON TWO PARALLEL OPTICAL AXES, A TUBULAR CASING WHEREING SAIDZOOM SYSTEM AND SAID CATADIOPTRIC SYSTEM ARE MOUNTED AND HOUSED, AN ENDWALL FORMED IN THE FRONT END OF SAID CASING AND A CIRCULAR BEARINGSURFACE DEFINING AN OPENING FORMED THEREIN, A REAR CLOSURE WALLDEMOUNTABLY SECURED TO THE REAR END OF SAID CASING, A STATIONARYMOUNTING TUBE WHEREIN SAID ZOOM SYSTEM IS HELD, MEANS OPERATIVELY FORMEDON THE FORWARD END OF SAID STATIONARY TUBE AND FITTING SAID CIRCULARBEARING SURFACE FOR SUPPORTING SAID TUBE, INTERFITTING MEANS COOPERATINGFORMED IN SAID CLOSURE WALL AND ON THE REAR OF SAID STATIONARY MOUNTING